NSF ACCESS — short for Advanced Cyberinfrastructure Coordination Ecosystem: Services & Support — is the National Science Foundation’s national program for allocating supercomputing, cloud, storage, and other advanced-computing resources to U.S.-based researchers and educators. It replaced the older XSEDE (Extreme Science and Engineering Discovery Environment) program, which formally ended operations in 2022, taking over as NSF’s primary mechanism for connecting researchers to a nationwide network of high-performance computing (HPC) systems hosted at university and national-lab data centers.
For research administrators, the point of confusion ACCESS most often creates is governance, not technology: it is a national, merit-reviewed allocation program, not a local recharge center — the campus core facility billing model most research offices are already used to administering. This guide explains how ACCESS allocations actually work, who can request them, and how the governance model differs structurally from a campus HPC recharge/chargeback operation, so research administrators can advise investigators correctly on which route applies to a given project.
What NSF ACCESS Is
ACCESS is funded by NSF but operated through a consortium of partner organizations rather than run directly out of a single NSF office. Researchers request time on participating systems — called Resource Providers (RPs) — through a single national request process rather than applying separately to each computing center. Resources available through ACCESS include traditional supercomputing clusters, GPU-accelerated nodes for machine-learning workloads, large-memory systems, cloud computing environments, and dedicated research storage.
Critically, using an ACCESS-allocated resource does not require the requester to already hold an NSF grant. A graduate student, postdoc, or faculty member can request an allocation directly, independent of whether the underlying research is NSF-funded, NIH-funded, internally funded, or unfunded exploratory work — a structural difference from many other federal resource programs that require an existing award as a prerequisite.
How ACCESS Allocations Work: Credits and Tiers
ACCESS uses a common currency called ACCESS Credits, which researchers exchange for resource-specific allocations at whichever Resource Provider system best fits their workload (exchange rates vary by system and resource type — compute, GPU, storage — and each Resource Provider approves, modifies, or declines the exchange based on fit). Allocations are organized into four tiers of increasing size and review burden:
- Explore ACCESS — for small resource needs; requires only a short abstract to submit, with roughly half the requested credit limit awarded up front and the remainder released after a progress report.
- Discover ACCESS — for modest-scale research activity; requires a one-page project description using ACCESS’s template, same credit-release structure as Explore.
- Accelerate ACCESS — for projects needing substantially more resources; requires a fuller (roughly three-to-five-page) project description.
- Maximize ACCESS — for projects that exceed what Accelerate can support, with no fixed upper limit on allocation size; requires a comprehensive proposal reviewed semi-annually by the ACCESS Allocation Review Committee (AARC).
Explore, Discover, and Accelerate requests are reviewed on a continuous, rolling basis (typically decided within about two weeks) against common merit criteria — methodology, research plan, and resource-use efficiency — rather than at fixed annual deadlines. Maximize requests go through the more formal AARC review, applying criteria consistent with standard NSF review emphases on intellectual merit and resource efficiency.
Who Is Eligible
To serve as the lead (PI) on an ACCESS allocation, an applicant must generally be:
- A U.S.-based researcher or educator at the graduate-student level or higher (graduate students may lead Explore/Discover requests but need a faculty co-PI/advisor);
- Affiliated with an eligible organization — an academic institution, nonprofit, federally funded research and development center (FFRDC), U.S. military academy, or, in some cases, a commercial entity;
- Using an institutional email address matching that affiliation (generic consumer email addresses are not accepted).
Postdoctoral researchers at U.S. institutions, K-12 teachers requesting resources for classroom use, and designated CI (cyberinfrastructure) Facilitators or Campus Champions are also explicitly eligible under defined conditions. Undergraduates cannot serve as PI. International researchers generally need a U.S.-based PI of record on the request.
How ACCESS Differs From a Campus HPC Recharge Model
Research administrators who manage or budget for a local core facility / research core — including a campus HPC cluster run as an internal service center or recharge center — are used to a fundamentally different governance and funding logic than ACCESS uses. The two models are not competitors so much as different tools for different situations, and many institutions offer both in parallel:
| Dimension | NSF ACCESS | Campus HPC Recharge Center |
|---|---|---|
| Who allocates access | National program; peer/merit review against common criteria, or lightweight review for small requests | Local institution; typically first-come/queue-based or capacity-managed by the facility’s own governance committee |
| How cost is recovered | Resources are NSF-funded and provided to the researcher without a bill; there is no direct charge-back to the PI’s grant for the ACCESS Credits themselves | Costs are recovered through user fees/billing rates charged to grants and departments, set under federal cost-accounting rules (2 CFR 200 Uniform Guidance) so the center neither profits nor is subsidized beyond disclosed limits |
| Prerequisite funding | None required — allocation can be requested independent of holding a specific grant | None required to use the facility, but usage is billed against whatever account/grant the PI designates |
| Scale of resources | National-tier supercomputing, GPU clusters, and storage at multiple Resource Provider institutions | Scaled to what a single institution has capitalized and staffed locally, generally smaller than flagship national systems |
| Typical use case in a grant budget | Cited as an available resource in the Facilities, Equipment, and Other Resources section of a proposal; no line-item cost to budget for the credits themselves | Budgeted as a direct cost line item (service center rate x usage), subject to the facility’s federally negotiated or institutionally approved billing rate |
The practical upshot for a research administrator: if an investigator needs computing capacity beyond what the campus recharge center can provide (or the campus has no HPC core facility at all), ACCESS is the route to national-scale resources without a subaward or a new line item in the budget for compute costs. If the work needs guaranteed, locally managed capacity with dedicated support staff and predictable turnaround, the campus recharge center remains the more appropriate — and typically faster to provision — option. The two are frequently used together: a lab might run day-to-day development work on a local recharge-billed cluster and burst to an ACCESS-allocated national system for large production runs.
Budgeting and Proposal Implications
Because ACCESS provides resources in kind rather than for a direct fee to the PI, it is generally described in a proposal’s Facilities, Equipment, and Other Resources narrative rather than budgeted as a direct cost. Research administrators reviewing a proposal that references ACCESS should check that:
- The investigator has (or has a credible plan to obtain) an active ACCESS allocation matched to the scale of computing the proposal describes — reviewers can and do question a Maximize-scale computational plan backed only by an Explore-tier allocation;
- No duplicate direct-cost line item for the same compute time has been added to the budget, since ACCESS credits themselves are not purchased with grant funds;
- Any locally billed recharge-center usage that supplements the ACCESS allocation (e.g., local storage, data staging, or specialized local hardware not available through an ACCESS Resource Provider) is budgeted separately and correctly, since that portion is a genuine chargeable direct cost.
Governance and Funding Structure
ACCESS is NSF-funded but is operated through a consortium structure rather than a single federal office processing every request. Individual computing systems are contributed by Resource Providers — typically universities, national laboratories, and supercomputing centers — each of which independently owns, operates, and staffs its own hardware while participating in the shared national allocation and support ecosystem. The ACCESS Allocation Review Committee (AARC) is the volunteer body that reviews the largest (Maximize-tier) requests using criteria aligned with NSF’s standard intellectual-merit and resource-efficiency review emphases.
Frequently Asked Questions
Does an ACCESS allocation cost the researcher or their grant money?
No. ACCESS provides computing time and storage as an in-kind national resource; there is no direct fee charged to the PI or their grant for the ACCESS Credits themselves. Costs may still arise for supplementary local services (e.g., a campus recharge center’s data-staging or specialized-hardware fees) that fall outside what an ACCESS Resource Provider offers.
Do I need an NSF grant to request an ACCESS allocation?
No. ACCESS allocations can be requested independent of any specific funding source, including NSF awards. Eligibility is based on institutional affiliation and role (graduate student or higher), not on holding a particular grant.
What replaced XSEDE?
ACCESS replaced XSEDE as NSF’s national cyberinfrastructure allocation program; XSEDE formally ended operations in 2022, and projects previously allocated under XSEDE were transitioned into equivalent ACCESS allocation tiers.
How is an ACCESS allocation different from a subaward to a supercomputing center?
An ACCESS allocation is a resource grant of compute/storage capacity, administered through the national ACCESS process — it is not a subaward, does not involve a separate legal agreement with the Resource Provider, and does not need to be set up through your institution’s subrecipient monitoring process the way a genuine subaward to another institution would.
Can undergraduate students use ACCESS resources?
Undergraduates cannot serve as the PI of an ACCESS allocation, but they can be added as authorized users under a faculty or eligible PI’s allocation, similar to how they would be added as authorized users of a campus recharge-center HPC account.
For the campus-side counterpart to this national model — how a local shared-instrumentation or computing core facility is funded, governed, and billed under federal cost-accounting rules — see CASRAI’s guide to the core facility (research core), and for the software platforms institutions use to manage that local scheduling and billing, see core facility management software. For funding programs that pay for the equipment and facilities behind a core in the first place, see research infrastructure funding.
